Question
What is foetal ejection reflex? Explain how it leads to parturition?
✓
Answer
Vigorous contraction of the uterus at the end of the pregnancy causes expulsion/ delivery of the foetus. This process of delivery of the foetus (childbirth) is called parturition.
Parturition is induced by a complex neuroendocrine mechanism. The signals for parturition originate from the fully developed foetus and the placenta which induce mild uterine contractions called foetal ejection reflex. This triggers release of oxytocin from the maternal pituitary. Oxytocin acts on the uterine muscle and causes stronger uterine contractions, which in turn stimulates further secretion of oxytocin.
The stimulatory reflex between the uterine contraction and oxytocin secretion continues resulting in stronger and stronger contractions. This leads to expulsion of the baby out of the uterus through the birth canal-parturition. Soon after the infant is delivered, the placenta is also expelled out of the uterus.
Parturition is induced by a complex neuroendocrine mechanism. The signals for parturition originate from the fully developed foetus and the placenta which induce mild uterine contractions called foetal ejection reflex. This triggers release of oxytocin from the maternal pituitary. Oxytocin acts on the uterine muscle and causes stronger uterine contractions, which in turn stimulates further secretion of oxytocin.
The stimulatory reflex between the uterine contraction and oxytocin secretion continues resulting in stronger and stronger contractions. This leads to expulsion of the baby out of the uterus through the birth canal-parturition. Soon after the infant is delivered, the placenta is also expelled out of the uterus.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Describe the human female reproductive system.
Write critical notes on the following :
(a) Eutrophication
(b) Biological magnification
(c) Ground water depletion and measures for its replenishment
(a) Eutrophication
(b) Biological magnification
(c) Ground water depletion and measures for its replenishment
Define a cistron. Giving examples differentiate between monocistronic and polyeistronic transcription unit.
Study the graph given below and answer the questions that follow:
- 5th day to 12th day of the cycle.
- 14th day of the cycle.
- 16th day to 25th day of the cycle.
a. Describe aminoacylation of tRNA.
b. Explain the process that takes place in the ribosomes when mRNA makes its entry into it in a prokaryote.
c. Due to transcription error, ATG codon of DNA is transcribed into UAG in mRNA which translates a nonfunctional polypeptide chain in the ribosome. Justify the statement.
b. Explain the process that takes place in the ribosomes when mRNA makes its entry into it in a prokaryote.
c. Due to transcription error, ATG codon of DNA is transcribed into UAG in mRNA which translates a nonfunctional polypeptide chain in the ribosome. Justify the statement.
Write short note on cancer.
Explain the two complexities that are observed in the process of transcription in eukaryotes and not in prokaryotes.
i. How are the characteristic features of pollen, anther and stigma of a maize plant suited for pollination by wind?
ii. How do you justify that:
1. Pollen grains are recovered from fossils?
2. Micropyle remains as a small pore in the seed coat of a fully developed seed?
ii. How do you justify that:
1. Pollen grains are recovered from fossils?
2. Micropyle remains as a small pore in the seed coat of a fully developed seed?
Write any four ways used to introduce a desired DNA segment into a bacterial cell in recombinant technology experiments.
- Explain the phenomenon of multiple allelism and co-dominance taking ABO blood group as an example,
- What is the phenotype of the following:
- IAi
- ii